A living organism is made up of cells. Cells are the smallest structures capable of maintaining life and reproducing. Cells have differing structures to perform different tasks. A tissue is an organization of a great many similar cells with varying amounts and kinds of nonliving, intercellular substances between them. An organ is an organization of several different kinds of tissues so arranged that together they can perform a special function.
Surgery is defined as a branch of medicine concerned with diseases requiring operative procedures.
Although many surgical procedures are successful, there is always a chance of failure. Depending on the type of procedure these failures can result in pain, need for re-operation, extreme sickness, or death. At present there is no reliable method of predicting when a failure will occur. Most often the failure occurs after the surgical procedure has been completed. Failures of surgical procedures can take many forms. The most difficult failures to predict and avoid are those that involve biological tissue. This difficulty arises for three distinct reasons. Firstly, the properties that favor the continued function of biological tissue are very complex. Secondly, these properties are necessarily disrupted by surgical manipulation. Finally, the properties of biological tissues vary between patients.
During a surgical operation, a variety of surgical instruments are used to manipulate biological tissues. However, traditional surgical instruments do not have the ability to obtain information from biological tissues. Obtaining information from the biological tissues that surgical instruments manipulate can provide a valuable dataset that at present is not collected. For example, this dataset can quantitatively distinguish properties of tissues that will result in success or failure when adapted to specific patient characteristics.
Surgical instruments that incorporate sensors onto the instruments' working surfaces are described, e.g., in U.S. patent application Ser. No. 10/510,940 and in U.S. Pat. No. 5,769,791. The instruments described in the prior art have the ability to sense tissue properties; however, their utility is limited by an inability to account for the multitude of differences that exist between patients. This limitation of the prior art is clearly illustrated by the fact that the instruments generate feedback after sensor signals are compared to a fixed dataset within the device. Thus, the prior art instruments have no means of adapting to patient-specific characteristics that are of utmost importance in avoiding surgical procedure failure. PCT Patent Application No. PCT/US2006/013985 describes a novel system and methodology for using the information gathered by surgical instruments having sensors in an adaptive, patient-specific manner.
Each surgical procedure has the potential for failure. A common procedure in gastrointestinal surgery is a bowel resection—removing the affected portion of the bowel and then mechanically joining the ends of the remaining segments to re-establish bowel continuity. The mechanical connection of the free ends of bowel forms what is termed a surgical anastomosis. A surgical anastomosis is formed by either traditional techniques using suture material, or by contemporary techniques utilizing surgical staplers. A surgical stapler mechanically joins the bowel by firing a pattern of staples from a cartridge or housing through the two free ends of bowel against an anvil that ultimately forms a securing crimp on the opposing side. There are many embodiments of surgical staplers. Some staplers form linear staple patterns, while others form circular patterns. Some staplers incorporate functionality for cutting tissue. Many staplers have the ability to vary the gap between the base of the staple and the formed crimp.
Anastomotic failure is one of the most feared complications of gastrointestinal surgery due to the resultant morbidity and mortality. Failure of an anastomosis, or intestinal junction, can cause a spectrum of morbidities to the patient including local abscess formation—requiring procedural drainage, tumor recurrence, debilitating pain, dysfunctional defecation, and overwhelming bacterial sepsis resulting in death. Despite improvements in surgical technique, there remains limited ability to assess the anastomotic segment and predict outcome, and as a result anastomotic failure occurs at unacceptably high levels given the severe consequences. For example, in the performance of a low anterior resection (LAR) for excision of rectal cancer, anastomotic failure has been reported to occur in up to 30% of cases. One large multicenter, observational study of 2729 patients reported a leak rate of 14.3%. These anastomotic failures cause a significant and avoidable economic burden on the healthcare system, as well as an incalculable amount of pain, suffering, and hardship for the patients in which the failure occurs. As a precaution many surgeons will avoid creating an anastomosis at the time of surgery and tunnel the free ends of the bowel through the abdominal wall to form a diverting stoma. The rationale of this maneuver is to prevent the leakage of fecal matter into the abdominal cavity from a potential anastomotic failure. Many times the surgeons will perform another procedure to reverse the stoma months after the initial procedure. In the same multicenter study 881 patients were given a temporary diverting stoma to mitigate the risk of an anastomotic leak, however, within this group only 128 patients developed a leak. Thus up to 85% of those patients underwent an additional surgical procedure to reverse the stoma that provided questionable benefit. The arbitrary creation of a temporary diverting stoma, and the eventual reversing procedure presents a significant and avoidable economic burden on the healthcare system, as well as exposes numerous patients to arguably unnecessary surgical risk. Presently, there is no reliable method or device available for predicting anastomotic failure, nor objective criteria by which to decide when a diverting stoma is indicated. Nor is there a device that can help to determine the optimal placement of an anastomosis.
There exists a need for a device, system and methodology for reducing anastomotic failures through the analysis of target tissues before, during, and after the creation of an anastomosis. There also exists a need to objectively determine, at the time of surgery, those patients that would benefit from a diverting stoma procedure. There also exists a need to deliver adjunct therapies to the anastomotic site to optimize outcome.
To accomplish its goal, the present invention couples to the desired stapling platform, which includes traditional off-the-shelf disposable surgical staplers, and uses an array of multimodality sensors to access the viability of the tissues at hand. If tissues are determined to be not suitable for an anastomosis, the present invention alerts the operative team to take corrective action, thus reducing the risk anastomotic failure. If after performing the anastomosis, the tissues are determined to be at high risk for failure, the present invention alerts the operative team to take corrective action.
One representative application of the present invention is in the treatment of colorectal cancer. Colorectal cancer (CRC) is the third most common cause of cancer for men and women in developed countries. Estimates predict that worldwide just under 1.2 million new cases of colorectal cancer were diagnosed in 2007. Rectal cancer accounts for approximately 27% of all colorectal cancers and presents the formidable challenge of ensuring a curative resection while maintaining acceptable function. The mainstay of treatment for rectal cancer is surgical resection—removing the affected portion of the bowel and performing an anastomosis on the ends of the remaining segments to re-establish bowel continuity. The end-to-end anastomosis (EEA) is most commonly performed using circular EEA staplers. As with any surgical procedure, resection of a rectal cancer can have complications. Amongst all of the possible complications the three most devastating to the patient in terms of morbidity and mortality are tumor recurrence, anastomotic leak and anastomotic stricture. Tumor recurrence can be reduced by: following oncologic principles of dissection, providing appropriate adjunctive chemotherapeutic, photodynamic, and radiation therapies, and preventing extra-luminal extravasation of residual intra-luminal neoplastic cells through anastomotic breakdown. Anastomotic failure has been anecdotally attributed to inadequate tissue perfusion and excessive tension at the anastomosis.
When determining the location of a rectal cancer the surgeon notes the distance of the tumor from the anal verge. The anal canal extends from 0-4 cm past the anal verge, and the rectum 4-19 cm. Surgically the rectum extends from the anal sphincters to the sacral promontory. The location of the cancer dictates the type of surgical procedure performed.
The primary goal of a curative resection is to remove all potential tissues harboring cancerous cells. To accomplish this goal, the surgical team aims to resect the tumor with a cancer free margin as well as the tumor's blood supply and draining lymphatic tissue. Tumors located in the upper rectum, greater than 12 cm from the anal verge, are regularly amenable to an anterior resection (AR). Those in the mid rectum, between 6-12 cm, are subject to a LAR with or without a total mesorectal excision (TME), and tumors in the lower rectum, 4-6 cm, are usually treated with an ultra-low anterior resection (ULAR), incorporating a TME, and either a colorectal or coloanal anastomosis. A total mesorectal excision is a technique that attempts to resect the rectum and all investing soft tissues en-bloc. This technique has been touted in the literature as having superior results in terms of minimizing local tumor recurrence, however it is speculated that the procedure has an inverse effect on leak rates due to the excision of the supplying vasculature to the anastomotic site. Every attempt is made to retain fecal continence, however those tumors involving the anal sphincters 0-4 cm are resected through a sphincter sacrificing abdominoperineal resection (APR).
As a secondary goal the surgical team strives to restore continuity of the bowel and ensuing fecal stream. To accomplish this goal an anastomosis is formed. Simply, an anastomosis is the surgical connection of two free ends of a tubular structure. When the continuity of the bowel cannot be restored, the fecal stream is diverted through a stoma, or opening, in the anterior abdominal wall through which the patient eliminates into an ostomy bag. There are two main reasons for stoma formation: resection of the anal sphincter complex, and diversion of the fecal stream. In a sphincter sacrificing procedure such as an APR, the patient is dependent on a permanent ostomy. With a sphincter sparing procedure such as a LAR, the fecal stream may diverted through a temporary ostomy in order to mitigate the risk of overwhelming sepsis resulting from fecal contents entering the abdominal cavity should there be a leak at the anastomosis. Most of the time a temporary stoma can be reversed within a few months after the initial operation through a separate procedure.
Anastomotic failure can cause a spectrum of morbidities to the patient including local abscess formation—requiring procedural drainage, tumor recurrence, debilitating pain, dysfunctional defecation, and overwhelming bacterial sepsis resulting in death. The scientific literature suggests that the cause of anastomotic failure is that inadequate tissue perfusion as a result of redefined vasculature, tissue interaction forces, edema, and tension result in a decrease of oxygen delivered to the anastomotic site. Without adequate oxygen delivery efficient aerobic cell respiration cannot occur within the native cells leading to tissue degradation, collagen matrix cannot mature into strong collagen fibrils, and white blood cells cannot effectively fight bacterial invasion.